In most motor vehicles, a fungus odor or other bad smells is generated during the use of an air conditioner. This is because bacteria, fungi and the like live on the surface of an evaporator.
In recent years, many different methods for the removal of smells generated from an evaporator have been proposed. As one example, there is available a technology in which bacteria, fungi and the like are sterilized and removed by irradiating anions or cations toward the surface of an evaporator.
In order to effectively remove smells generated from an evaporator, it is important to precisely predict the smell generation time. By doing so, it becomes possible to efficiently sterilize and deodorize the evaporator in conformity with the smell generation time. This makes it possible to suppress, to the utmost limit, generation of a fungus odor or other bad smells in the evaporator.
There is known a method of predicting the smell generation time in an evaporator through the use of a humidity sensor.
This method takes advantage of the principle under which a fungus odor or other bad smells is increased along with the increase in the surface humidity of an evaporator. The surface humidity of the evaporator is detected by a humidity sensor. Determination is made as to whether the detected surface humidity of the evaporator is equal to or higher than a predetermined reference humidity. If the result of determination is affirmative, it is predicted that smells will be increased in the evaporator.
In this conventional technology, the generation of a fungus odor or other bad smells is predicted only based on the humidity data obtained from a partial surface region of the evaporator. Thus, the conventional technology suffers from a drawback in that the prediction accuracy of the smell generation time is not so high.
This drawback leads to a reduction in the evaporator sterilizing and deodorizing efficiency. This makes it difficult to effectively cope with the generation of a fungus odor or other bad smells.
Moreover, the conventional technology employs an expensive humidity sensor in order to detect the surface humidity of the evaporator, which results in an increase in the manufacturing cost.
In addition, the conventional technology of predicting the smell generation time is configured to predict the smell generation time based on a predetermined reference humidity. For that reason, the conventional technology is not suitable for a vehicle occupant who is very sensitive to smells and can sense a fungus odor or other bad smells even below the reference humidity.
Thus, the conventional technology cannot adapt itself to different smell sensing abilities and different smell sensitivities of individual vehicle occupants, consequently making many users feel inconvenient.